Buggy code:
@ EventHandler public void preInit ( FMLPreInitializationEvent event ) { Main . MyCreativeTab_1 = new CreativeTabs ( "MyCreativeTab_1" ) { public ItemStack getIconItemStack ( ) { return new ItemStack ( Main . MyFood_1 , 1 , 0 ) ; } } ; Main . MySword_1 = new mymod . items . MySword ( 2021 , Main . MyToolMaterial , "MySword_1" ) . setCreativeTab ( Main . MyCreativeTab_1 ) ; GameRegistry . registerItem ( Main . MySword_1 , "MySword_1" ) ; LanguageRegistry . addName ( Main . MySword_1 , "Death<seq2seq4repair_space>Sword" ) ; Main . MyPickaxe_1 = new mymod . items . MyPickaxe ( 2022 , Main . MyToolMaterial , "MyPickaxe_1" ) . setCreativeTab ( Main . MyCreativeTab_1 ) ; GameRegistry . registerItem ( Main . MyPickaxe_1 , "MyPickaxe_1" ) ; LanguageRegistry . addName ( Main . MyPickaxe_1 , "Death<seq2seq4repair_space>Pickaxe" ) ; Main . MyItem_1 = new MyItem ( 2030 , "MyItem_1" ) . setCreativeTab ( setCreativeTab ) . setMaxStackSize ( 64 ) ; setCreativeTab ( Main . MyCreativeTab_1 ) ; GameRegistry . registerItem ( Main . MyItem_1 , "MyItem_1" ) ; LanguageRegistry . addName ( Main . MyItem_1 , "Blood" ) ; Main . MyFood_1 = new mymod . items . MyFood ( 2040 , 8 , 80.8F , true , "MyFood_1" ) . setAlwaysEdible ( ) . setPotionEffect ( Potion . invisibility . id , 600 , 60 , 1.0F ) . setCreativeTab ( setCreativeTab ) . setCreativeTab ( Main . MyCreativeTab_1 ) ; GameRegistry . registerItem ( Main . MyFood_1 , "MyFood_1" ) ; LanguageRegistry . addName ( Main . MyFood_1 , "Expeiment<seq2seq4repair_space>1" ) ; Main . MyFood_2 = new mymod . items . MyFood ( 2041 , 0 , 0.0F , true , "MyFood_2" ) . setAlwaysEdible ( ) . setPotionEffect ( Potion . nightVision . id , 600 , 60 , 1.0F ) . setCreativeTab ( setCreativeTab ) . setCreativeTab ( Main . MyCreativeTab_1 ) ; GameRegistry . registerItem ( Main . MyFood_2 , "MyFood_2" ) ; LanguageRegistry . addName ( Main . MyFood_2 , "Expeiment<seq2seq4repair_space>2" ) ; Main . MyFood_3 = new mymod . items . MyFood ( 2042 , 8 , 80.8F , true , "MyFood_3" ) . setAlwaysEdible ( ) . setPotionEffect ( Potion . regeneration . id , 600 , 60 , 1.0F ) . setCreativeTab ( setCreativeTab ) . setCreativeTab ( Main . MyCreativeTab_1 ) ; GameRegistry . registerItem ( Main . MyFood_3 , "MyFood_3" ) ; LanguageRegistry . addName ( Main . MyFood_3 , "Expeiment<seq2seq4repair_space>3" ) ; Main . MyFood_4 = new mymod . items . MyFood ( 2043 , 0 , 0.8F , true , "MyFood_4" ) . setAlwaysEdible ( ) . setPotionEffect ( Potion . wither . id , 80 , 60 , 1.0F ) . setCreativeTab ( setCreativeTab ) . setCreativeTab ( Main . MyCreativeTab_1 ) ; GameRegistry . registerItem ( Main . MyFood_4 , "MyFood_4" ) ; LanguageRegistry . addName ( Main . MyFood_4 , "Expeiment<seq2seq4repair_space>4" ) ; Main . MyFood_5 = new mymod . items . MyFood ( 2044 , 8 , 80.8F , true , "MyFood_5" ) . setAlwaysEdible ( ) . setPotionEffect ( Potion . resistance . id , 60 , 60 , 1.0F ) . setCreativeTab ( setCreativeTab ) . setCreativeTab ( Main . MyCreativeTab_1 ) ; GameRegistry . registerItem ( Main . MyFood_5 , "MyFood_5" ) ; LanguageRegistry . addName ( Main . MyFood_5 , "Expeiment<seq2seq4repair_space>5" ) ; Main . MyBlock_1 = new mymod . blocks . MyBlock ( 250 , net . minecraft . block . material . Material . rock , "MyBlock_1" ) . setLightValue ( 50.0F ) . setResistance ( 50.0F ) . setHardness ( 5.8F ) . setStepSound ( Block . soundGrassFootstep ) . setCreativeTab ( Main . MyCreativeTab_1 ) ; GameRegistry . registerBlock ( Main . MyBlock_1 , "MyBlock_1" ) ; LanguageRegistry . addName ( Main . MyBlock_1 , "Death<seq2seq4repair_space>Head<seq2seq4repair_space>Ore" ) ; MinecraftForge . setBlockHarvestLevel ( Main . MyBlock_1 , "pickaxe" , 0 ) ; <START_BUG> Main . MyBlock_2 = new mymod . blocks . MyBlock ( 250 , net . minecraft . block . material . Material . rock , "MyBlock_2" ) . setLightValue ( 0.0F ) . setResistance ( 40.0F ) . setHardness ( 4.8F ) . setStepSound ( Block . soundGrassFootstep ) . setCreativeTab ( Main . MyCreativeTab_1 ) ; <END_BUG> GameRegistry . registerBlock ( Main . MyBlock_2 , "MyBlock_2" ) ; LanguageRegistry . addName ( Main . MyBlock_2 , "Death<seq2seq4repair_space>Head<seq2seq4repair_space>Ore" ) ; MinecraftForge . setBlockHarvestLevel ( Main . MyBlock_2 , "pickaxe" , 0 ) ; Main . MyHelmet_1 = new mymod . armor . MyArmor ( 2060 , Main . MyArmorMaterial_1 , 0 , 0 , "myarmor" ) . setCreativeTab ( Main . MyCreativeTab_1 ) ; GameRegistry . registerItem ( Main . MyHelmet_1 , "MyHelmet_1" ) ; LanguageRegistry . addName ( Main . MyHelmet_1 , "Black<seq2seq4repair_space>Helmet" ) ; Main . MyChest_1 = new mymod . armor . MyArmor ( 2061 , Main . MyArmorMaterial_1 , 0 , 1 , "myarmor" ) . setCreativeTab ( Main . MyCreativeTab_1 ) ; GameRegistry . registerItem ( Main . MyChest_1 , "MyChest_1" ) ; LanguageRegistry . addName ( Main . MyChest_1 , "Black<seq2seq4repair_space>Chest" ) ; Main . MyLeggings_1 = new mymod . armor . MyArmor ( 2062 , Main . MyArmorMaterial_1 , 0 , 2 , "myarmor" ) . setCreativeTab ( Main . MyCreativeTab_1 ) ; GameRegistry . registerItem ( Main . MyLeggings_1 , "MyLeggings_1" ) ; LanguageRegistry . addName ( Main . MyLeggings_1 , "Black<seq2seq4repair_space>Leggings" ) ; Main . MyBoots_1 = new mymod . armor . MyArmor ( 2063 , Main . MyArmorMaterial_1 , 0 , 3 , "myarmor" ) . setCreativeTab ( Main . MyCreativeTab_1 ) ; GameRegistry . registerItem ( Main . MyBoots_1 , "MyBoots_1" ) ; LanguageRegistry . addName ( Main . MyBoots_1 , "Black<seq2seq4repair_space>Boots" ) ; Main . MyHelmet_2 = new mymod . armor . MyNinjaArmor ( 2064 , Main . MyArmorMaterial_1 , 0 , 0 , "myninjaarmor" ) . setCreativeTab ( Main . MyCreativeTab_1 ) ;

Fix:
Main . MyBlock_2 = new mymod . blocks . MyBlock ( 251 , net . minecraft . block . material . Material . rock , "MyBlock_2" ) . setLightValue ( 0.0F ) . setResistance ( 40.0F ) . setHardness ( 4.8F ) . setStepSound ( Block . soundGrassFootstep ) . setCreativeTab ( Main . MyCreativeTab_1 ) ;